Feline Respiratory Diseases Quiz

Respiratory Disease in Dogs, Cats, and Rabbits

• This presentation covers respiratory diseases in dogs, cats, and rabbits
• Topics include learning objectives, constructing a differential diagnosis, clinical presentation, common causes in cats and dogs, and treatment/prevention

Learning Objectives

• Construct differential diagnosis list based on clinical presentation and choose appropriate diagnostics
• Determine appropriate medical and surgical interventions in the management/treatment of airway diseases in dogs, cats, and rabbits
• Determine appropriate prognosis, and welfare implications of treatment options
• Determine control measures for disease prevention

Constructing a Differential Diagnosis: History

• Signalment (age, breed predispositions)
• When did it start?
• How did it start?
• Has it changed?
• Has it happened before?
• Vaccinations?
• Recent travel/changes in management/others affected?
• Other signs (e.g., vomiting, diarrhea)
• Any pre-existing conditions?
• Receiving medications?
• Trauma or toxin ingestion?

Constructing a Differential Diagnosis: Clinical Presentation

Upper Respiratory Tract Disease

• Sneezing
• Nasal discharge
• Stridor/stertor
• Increased inspiratory effort
• Facial deformity/pain
• Altered vocalization/loss of voice

Lower Respiratory Tract Disease

• Coughing
• Dyspnea or tachypnea
• Exercise intolerance
• Respiratory distress/cyanosis
• Other systemic signs

Common Causes of URT Disease in Cats

Feline Upper Respiratory Tract Infections

• Usually viral, common in multi-cat households/catteries
• Feline Herpesvirus (FHV-1/Feline rhinotracheitis virus) often associated with sneezing, ocular discharge, conjunctivitis, keratitis, corneal ulcers, and chronic rhinitis
• Feline Calicivirus (FCV) often associated with oral ulceration, sneezing, nasal discharge, chronic stomatitis, gingivitis, and pneumonia (severe cases)

Chronic Rhinosinusitis

• Chronic inflammatory condition, typically post-viral (secondary to FHV-1 or FCV)
• Damage to nasal turbinates reduces mucosal immunity and leads to chronic secondary infection
• Persistent or recurrent nasal discharge (mucopurulent)
• Sneezing
• Nasal obstruction
• Rule out other causes
• Radiography
• Rhinoscopy with biopsy for histopathology
• Advanced imaging (CT or MRI) for sinus assessment

Allergic Rhinitis

• Caused by allergens (e.g., pollens, dust mites, mold, cleaning agents)
• Less common than post-viral chronic rhinosinusitis
• Sneezing (often intermittent)
• Nasal discharge (typically serous/mucopurulent if secondary bacterial)
• Pawing at nose/face
• Conjunctivitis (frequently)
• Cough/wheezing (severe cases, possible allergic bronchitis/feline asthma)

Nasopharyngeal Foreign Bodies

• Commonly long grass blades lodged in nasopharynx
• Sneezing
• Unilateral nasal discharge (serous, mucopurulent, or hemorrhagic)
• Gagging, coughing, or reverse sneezing (especially if lodged in caudal nasal passages/nasopharynx)
• Pawing at face/nose
• Halitosis (secondary bacterial infection)
• Open-mouthed breathing/stridor (severe cases)

Nasopharyngeal Polyps

• Benign pedunculated growths arising from the middle ear or nasopharynx
• Chronic nasal discharge (unilateral)
• Stertor, difficulty breathing, possible dysphagia
• Otitis externa/media, vestibular signs, Horner's syndrome (if extending into middle ear)
• Visual examination (otoscopy/rhinoscopy) and imaging (radiography)
• Histopathological examination after excision

Fungal Rhinitis

• Rare in UK
• Emerging disease in cats worldwide caused by Cryptococcus, Aspergillus, and Penicillium species
• Chronic nasal discharge, epistaxis
• Stertor
• Facial swelling
• Neurological signs (seizures, blindness) if CNS involvement
• Serology (Cryptococcus spp)
• Imaging (radiography, endoscopy, turbinate lysis often seen on CT)
• Cytology and fungal plaque culture

Feline Asthma (Feline Allergic Airway Disease)

• Common lower airway inflammatory disease, allergic in origin
• Cough (inducible on tracheal palpation)
• Increased expiratory effort/wheeze
• Open-mouth breathing
• Tachypnea
• Vomiting

Common Causes of LRT Disease in Dogs

Infectious Tracheobronchitis/Canine Infectious Respiratory Disease Complex (Kennel Cough)

• High contagious viral/bacterial condition (Canine parainfluenza virus, Canine Adenovirus, Bordetella bronchiseptica)
• Harsh, hacking cough (often described as "goose honk")
• Nasal discharge
• Mild lethargy/pyrexia
• History (recent dog exposure)
• Deep oropharyngeal swab PCR test

Brachycephalic Obstructive Airway Syndrome (BOAS)

• Anatomical abnormalities in brachycephalic breeds (e.g., English/French Bulldogs, Pugs)
• Stenotic nares, aberrant/hypertrophied turbinates
• Elongated/collapse soft palate
• Narrow larynx/laryngeal hypoplasia/everted laryngeal saccules
• Hypoplastic trachea
• Skull base malformation
• Snoring/noisy breath (stertor/stridor)
• Increased respiratory effort
• Exercise intolerance
• Cyanosis/collapse
• Breed predisposition, clinical examination, endoscopic evaluation, radiographs/CT
• Surgical management (e.g., widening of narrow airways or resection)
• Weight management/avoiding stress/heat

Laryngeal Paralysis

• Paralysis of arytenoid cartilages, preventing airway opening
• Older, large-breed dogs (overrepresented in Labradors)
• Acquired form (damage to recurrent laryngeal nerve, intra- or extra-thoracic masses).
• Inspiratory stridor
• Exercise intolerance
• Coughing/dysphagia/regurgitation
• Dysphonia or change in bark
• Visual inspection (light anesthesia)
• Radiographs (masses or pneumonia)
• Neurological assessment
• Biochemistry/hematology to rule out endocrinopathies
• Surgical intervention(unilateral arytenoid lateralization)

Canine Nasal Aspergillosis

• Fungal condition, inhaled Aspergillus spores
• Dolichocephalic breeds are predisposed
• Chronic nasal discharge (serous, mucopurulent, or hemorrhagic)
• Nasal pain/discomfort
• Sneezing
• Epistaxis (nosebleeds)
• Ulceration/depigmentation of nares
• CT or radiographs (nasal turbinate destruction, tissue density increased)
• Rhinoscopy (visualizing fungal plaques in nasal cavity), cytology/culture/biopsy
• Surgical debridement of fungal plaques, topical clotrimazole instillation (every 2 weeks until negative culture/histopathology)
• Systemic antifungals (itraconazole/fluconazole; less effective than topical)

Chronic Bronchitis

• Thickening/distortion of bronchial walls, bronchiectasis, cor pulmonale
• Tracheobronchial collapse, hyperaemia, thickening/increase in mucous
• Lots of mucous, neutrophils in cytology
• Decreased oxygen saturation
• Glucocorticoids (oral/inhaled)
• Bronchodilators (e.g., theophylline)
• Nebulizers (saline/mucolytics)

Aspiration Pneumonia

• Aspiration of solid/liquid causes severe inflammatory response, alveolar damage
• Laryngeal dysfunction/megaesophagus/iatrogenic medication/vomiting
• Acute coughing/dyspnea, pyrexia/anorexia
• History, clinical signs. Radiography/ultrasound
• Supportive care (IV fluids, oxygen therapy, nutritional support)
• Antibiotics (broad spectrum with good pulmonary penetration)

Lungworm

• Parasitic infection with Angiostrongylus vasorum
• Dogs in contact with foxes, rodents that ingest snails/slugs/frogs are at high risk
• Subclinical/non-specific(lethargy, weight loss, vomiting)
• Pulmonary (cough, exercise intolerance, dyspnea)
• Coagulopathy (anemia, bleeding in the CNS)
• Cardiovascular signs (rare, possible myocarditis, heart murmurs, heart failure)
• Radiography/diffused bronchial thickening with interstitial lung pattern
• Endoscopy/variable and non-specific lung patterns/infiltrates
• Diagnostic tests like AngioDetect TM, in-house Baermann's, BAL cytology, and PCR
• Treatment with Moxidectin/imidacloprid, Milbemycin, Fenbendazole

Idiopathic Pulmonary Fibrosis

• Chronic and progressive interstitial lung disease
• Older West Highland White Terriers (WHWTs)
• Insidious onset, progression.
• Coughing
• Panting
• Respiratory distress/tachypnea
• Distinctive “Velcro crackle” on auscultation
• Cyanosis with minimal exertion
• Weakness/syncope
• Possible pulmonary hypertension

Common Causes of URT Disease in Rabbits

• Obligate nasal breathers, URT compromise significant

• Often termed "Snuffles", primary or secondary

• Usually bacterial but viral and fungal causes possible

• Dental disease, trauma, foreign bodies, neoplasia can cause URT signs

• Pasteurella multocida – often implicated

• Bordetella bronchiseptica, Pseudomonas species, Staphylococcus species, Moraxella catarrhalis, Mycoplasma species

• Can be inhaled into surrounding tissues(e.g., nasolacrimal duct, conjunctivae, eustachian tubes, middle ear, inner ear, LRT)

Rabbits: Snuffles Clinical Signs

• Nasal and ocular discharge
• Snuffling, increased inspiratory respiratory rate
• Matted fur
• Dyspnea/open-mouth breathing (severe disease)
• Epiphora, conjunctivitis, dacrocystitis
• Head shaking/scratching
• Head tilt/neurological signs
• Non-specific signs (weight loss, lethargy)

Rabbits: Diagnosis

• Full nose-tail clinical examination
• Hematology and biochemistry for general health
• Deep nasal swab (bilateral)
• Sedation or local anaesthesia
• Nasolacrimal flush/biopsy of nasal mucosa
• Radiographs (dental diseases)
• Endoscopy (small bore rigid endoscope)
• CT (detailed images)
• Ultrasound (rule out cardiac disease)

Rabbits: Treatment

• Accurate diagnosis
• 14 days (longer if chronic) of treatment
• Avoid fluoroquinolones (initial line)
• Supportive care (fluid therapy, nutrition, NSAIDs)
• Treatment failures = consider inaccurate diagnosis/different type of bacterial disease (e.g., abscesses/granulomas)
• Severe cases = surgery (rhinotomy/rhinostomy), flushing, and topical antibiotics

Rabbits: Lower Respiratory Disease

• No septa dividing lungs = generalized lung disease
• Respiration mainly diaphragmatic = increased intra-abdominal pressure
• Same infectious agents as URT
• Mycoplasma species and Chlamydophila species isolated in pneumonia cases
• Viral/mycobacterial disease rare
• Metastatic neoplasia/cardiovascular disease/trauma
• Dyspnea, abnormal/wheezing respiratory sounds,
• Radiography/ultrasound.
• Tracheal wash/BAL for suspect LRT disease

Rabbits: Prognosis, Welfare, Prevention

• Prognosis depends on underlying cause
• Often advanced before presentation
• Snuffles= very contagious, challenging to treat, guarded prognosis
• High welfare concern
• Strict hygiene/quarantine for new rabbits important
• Isolating/barrier nursing of sick rabbits
• Excellent husbandry practices essential

Further Reading

• Various peer-reviewed articles on the given topics, available through veterinary journals/databases